The present invention relates to an apparatus for use with a removable child seat in a vehicle having a seat belt webbing pretensioner. The present invention is particularly directed to an apparatus for disabling the seat belt webbing pretensioner associated with a given vehicle seat when a removable child seat is located on that vehicle seat.
It is known to sense the presence of a rearward facing infant child seat in a vehicle, and to prevent the actuation of an inflatable occupant restraint, such as an air bag, when the presence of such a child seat is sensed. The rearward facing infant child seat is detected using an identifiable tag attached to the child seat and an antenna coil mounted in the vehicle. The antenna coil transmits an EMF signal to the tag, which, in turn, returns a signal to the antenna coil indicating the presence of the rearward facing infant child seat on the vehicle seat.
It is also known to utilize a seat belt webbing pretensioner to help protect a vehicle occupant from injury during a vehicle collision. The seat belt webbing pretensioner is actuatable to retract seat belt webbing extending over the body of the vehicle occupant and thereby to remove any slack in the seat belt webbing immediately prior to the vehicle collision.
If a child seat is secured to a vehicle seat by seat belt webbing having an associated pretensioner, it is desirable to disable the pretensioner. It is further desirable to disable the pretensioner regardless of whether the child seat is rearward facing or forward facing or whether the child seat is located on a front seat of the vehicle or on a rear seat of the vehicle.
An apparatus for use with a removable child seat in a vehicle comprises a vehicle seat on which a removable child seat may or may not be present, and a seat belt webbing pretensioner for retracting seat belt webbing associated with the vehicle seat. A first sensor provides a first output signal in response to a vehicle collision of a magnitude above a predetermined threshold. A second sensor provides a second output signal in response to the presence of a child seat on the vehicle seat. A controller receives the first and second output signals and, in response to the first output signal, actuates the seat belt webbing pretensioner when a child seat is not present on the vehicle seat and inhibits actuation of the seat belt webbing pretensioner when a child seat is present on the vehicle seat.
A pretensioner actuation circuit for actuating the seat belt webbing pretensioner is electrically connected with and controlled by the controller. The second sensor comprises an antenna coil mounted in the vehicle and an identification tag for attachment to a child seat. The antenna coil is adapted to transmit an electromagnetic field (EMF) signal to the identification tag and to receive a return EMF signal from the identification tag. The identification tag is adapted to receive an EMF signal from the antenna coil and to use energy of the received EMF signal to generate a return EMF signal.
In accordance with certain embodiments of the present invention, the vehicle seat comprises one of a front passenger seat and a rear passenger seat and a child seat is locatable on the one passenger seat to face rearward of the vehicle.
In accordance with other embodiments of the invention, the vehicle seat comprises one of a front passenger seat and a rear passenger seat and a child seat is locatable on the one passenger seat to face forward of the vehicle.